I think always telling the truth is an important principle to keep in any relationship between people. Nevertheless, I also admit that people should be allowed to tell lies in some urgent situations when telling the truth may harm themselves or other people's happiness.
Firstly, believing in each other is crucial in all kinds of relationships. A close relationship relies heavily on trust between people. People are more willing to make friends with ones who are trustworthy. Not telling the truth will ruin people's trust and bring a lot of problems. If the business people do not believe in each other, their cooperation in commercial business will not be comfortable or productive. If the market does not inform its guests honestly about the product they sell, then no one will be eager to buy anything in this market. For a company, finances should be transparent and accessible to the public. If managers don't tell the actual situation of their companies, they will not expect any investment from society or any assistance from the government, which will severely jeopardize their business. In conclusion, telling the truth help to build a solid relationship in the long run, while not telling the truth will ruin the trust among people and devastate a relationship.
On the other hand, there is no doubt that sometimes we are not required to tell the truth. You can refuse to tell the truth when asked offensive questions. For example, asking the age of women is regarded as an inconsiderable behavior. Therefore, they are not required to tell the truth when asked about their age. What's more, sometimes lying is necessary to protect your security and sensitive personal information. For instance, lying is forgivable and inevitable when confronting violent criminals who force you to give out personal information, like address or card code, just to name a few. Before telling the truth, you should reconsider and make sure the truth you leak out will not be harmful to you or utilized by people with dangerous intentions.
In my opinion, trust is the central pillar in relationships among people. Therefore, we need to be honest with others and avoid telling lies, although in some urgent situations telling lies is forgivable.